Drawing Graphs from Equations Monday, 21 March 2016 A graph can be drawn from an equation. For example, draw the graph of: y = 2x + 1 This is the equation or RULE for drawing the graph

This is the graph of y = 2x + 1 x x x y 13579

To draw the graph of y = 2x + 1 draw a table like this putting in the x numbers x 01234

x x I want to find y = 2x + 1, so first, you find the value of the 2x. This means 2 X x so times each of the x numbers by 2.

x x x add on 1 to the 2x Remember, you want to find y = 2x + 1 so you add on 1 to the 2x to find the value of 2x + 1

x x x y You have done everything to the x number so now you have found the y number y = 2x + 1

x x x y Now, plot the value of x against the value of y on the graph’s axes.

x x x y Join up the points with a line

x x x y You can draw any graph in a similar way. y= 2x + 1

To draw the graph of y = 3x - 5 draw a table like this putting in the x numbers x Draw the graph of: y = 3x - 5

Find the value of 3x. You times all the x numbers by 3. x x Draw the graph of: y = 3x - 5

Take away 5 from the value of 3x. x x x Draw the graph of: y = 3x - 5

You have done all that the rule asks so you have the y value. x x x y Draw the graph of: y = 3x - 5

Plot the points x x x y Draw the graph of: y = 3x - 5

Join up the points with a straight line x x x y Draw the graph of: y = 3x - 5

Draw the graph of y = 6 – 2x x Draw a chart with x values 0 to 4

Draw the graph of y = 6 – 2x x x Find the value of 2x

Draw the graph of y = 6 – 2x x x – 2x Take 2x away from 6

Draw the graph of y = 6 – 2x x x – 2x y 6420 You have done all that the rule asks so you have the y value.

Draw the graph of y = 6 – 2x x x – 2x y6420 Now, you can plot the points and draw the graph.